In this Phase I Cutting-Edge Basic Research Awards (CEBRA) application, a proof-of-concept study to examine effects of treatment with d-cycloserine for facilitating extinction of craving provoked by repeated exposure to cigarette smoking cues is proposed. Smoking cues will be presented using an established virtual reality simulator. The benefits of this treatment approach together with cognitive behavioral treatment for reducing cigarette smoking will then be determined. The project's specific aims are to determine the effects of four weeks of once-weekly treatment with d-cycloserine or placebo on craving elicited by exposure to "virtual reality" smoking cues and then to determine the effects of this combined with cognitive behavioral treatment on frequency of cigarette smoking. Participants will receive smoking cessation treatment consisting of an orientation session followed by four weekly sessions consisting of 20 minutes of cognitive behavioral treatment followed by 35 min of exposure to smoking cues. Brief cognitive behavioral treatment is provided in addition to the virtual reality cue exposure in order to help participants cope with cigarette craving elicited by exposure to smoking cues. The project's primary hypothesis is that treatment with d-cycloserine prior to each exposure session will be associated with greater extinction of craving and that this together with cognitive behavioral treatment will be associated with reductions in cigarette smoking. In this Phase I Cutting-Edge Basic Research Awards (CEBRA) application, a proof-of-concept study to examine effects of treatment with d-cycloserine for facilitating extinction of craving provoked by exposure to cigarette smoking cues is proposed. This project may lead to the development of new treatment approaches for addictions. [unreadable] [unreadable] [unreadable]